Field of the Invention
The present invention is related to toughening epoxy resin compositions; and more specifically, the present invention is related to the use of a polyol and core shell rubber (CSR) toughening agents in epoxy resin compositions.
Background
There are various known methods for toughening epoxy-anhydride thermosets using a number of available known toughening agents such as CSRs or polyols. A major disadvantage in the use of CSRs as toughening agents in epoxy formulations is the significant increase in formulation viscosity. Compared to CSRs, polyols provide a lesser increase of the formulation viscosity, but they do not provide the same degree of increase in fracture toughness and induce a lower thermoset glass transition temperature (Tg).
It is therefore desired to provide a curable epoxy formulation with a toughening agent that will improve the toughness of the formulation with a minimal increase in formulation viscosity and with no decrease or detrimental affect on the Tg of the final thermoset made from the epoxy formulation.